Jose Mourinho suffered his first defeat since his return to the Premier League at Goodison Park as Everton hung on to a late-first-half goal for a 1-0 win on Saturday. Steven Naismith's header moments before half-time proved decisive as Chelsea wasted numerous chances and struggled to break down the Toffees midfield.
The Blues may lament an unawarded penalty when Oscar was caught in a defensive sandwich on the edge of the box, but the fact remains that Everton were able to execute their game plan more effectively.
Mourinho will have taken plenty of notes to work on, but here are six things we learned from this disappointing defeat.
Statistics taken from Four Four Two StasZone.